Commit a26ac2455ffc (move TREE_RCU from softirq to kthread) addedper-CPU kthreads. However, kthread creation uses kthread_create(), whichcan put the kthread's stack and task struct on the wrong NUMA node.Therefore, use kthread_create_on_node() instead of kthread_create()so that the stacks and task structs are placed on the correct NUMA node.

A similar change was carried out in commit 94dcf29a11b3 (kthread:use kthread_create_on_node()).